1. Field of the Invention
The present invention relates to an apparatus for physics and chemistry which processes an image obtained by photographing cells, and a method of processing the image.
2. Description of the Background Art
A screening which narrows down compounds serving as candidates for medical and pharmaceutical products is performed in the course of research and development of the medical and pharmaceutical products. An example of the screening includes: preparing a plurality of culture solutions into which biological cells are put; adding compounds to the culture solutions while changing various conditions to cultivate the cells; and narrowing down the compounds serving as candidates for medical and pharmaceutical products, based on the culture states of the cells.
In such a screening, a reagent has been hitherto used for the assessment of the culture states of the cells. Specifically, a reagent is applied to the cells to cause the fluorescence reaction of specific molecules in the cells. The culture states of the cells are judged by measuring the fluorescence intensity of the specific molecules in the cells. This method, however, has required the costly reagent, and also has required much time for the fluorescence reaction. In addition, this method has not been capable of observing changes in the same cell with time because the reagent destroys cell walls.
In recent years, three-dimensional culture such that cells are cultivated in three dimensions has been performed to investigate the effects of medical and pharmaceutical products in an environment closer to that in a living body. An important object to be observed in such three-dimensional culture is the state of spheroids which are three-dimensionally aggregated cell clumps. The aforementioned method of measuring the fluorescence is not suitable for the observation of the cell clumps.
For these reasons, an attempt has been made in recent years to develop an apparatus for observing the culture states of cells by photographing the cells at a high resolution without using any reagent. This apparatus photographs a well plate having a plurality of depressions or wells for culture at predetermined time intervals to clip images of each of the wells from the resultant photographed images. The clipped images are displayed on a display device, and are compared and analyzed, whereby the culture states of the cells in each well are assessed.
Conventional apparatuses for displaying the images of cells are disclosed, for example, in Japanese Patent Application Laid-Open No. 2010-151647 and in Japanese Patent Application Laid-Open No. 2011-64602.
The operation of assessing the culture states of the cells from the obtained images is performed by human visual judgment in principle. However, burdens on the human visual judgment are reduced if classification is made to some extent by using software in such an apparatus. Thus, the development of the technique of extracting objects presumed to be cells from images to classify the extracted objects as adopted or as not adopted has been advanced in recent years.
For classifying the objects as adopted or as not adopted, parameters such as the area and density of the objects in the images are measured. Then, each of the objects is classified as adopted or as not adopted, based on whether the measurement value for each object is within an allowable range or not. Appropriate setting of the allowable ranges of the parameters is important to increase the accuracy of the judgment as adopted or as not adopted using software.
A large number of parameters, however, are used for the judgment of the objects as adopted or as not adopted. It is a difficult operation for a user unskilled in image processing to appropriately adjust the allowable ranges of such a large number of parameters while viewing the results of judgment of the objects as adopted or as not adopted which are displayed on a screen. For this reason, there is a need for a technique capable of classifying objects as adopted or as not adopted and thereafter displaying the objects classified as adopted and the objects classified as not adopted in an easily distinguishable manner.